1. Field of the Invention
The present invention relates in general to a fluid product transfer system, and pertains, more particularly, to a system for transferring blood product between a blood storage bag and a processing bag, or vice versa. The principles of the present invention may be applied in a centrifuge processing system or other extracorporeal blood processing systems.
2. The Prior Art
In current blood processing systems there are generally two techniques for moving blood product from a flexible blood storage bag to a processing device such as a centrifuge. These two techniques include gravity and peristaltic pumps currently used to create blood flow in the coupling tubing.
Regarding the gravity technique, the blood storage bag is typically disposed at a position higher than the processing bag and blood flows from the bag to the lower disposed centrifuge by gravitational force. The gravitational technique is adequate if the bag is high enough, the tubing diameter large enough, and the tubing length is short enough to expedite fluid flow. For some applications in which the tubing inside diameter is narrow, the length of tubing is relatively long. Thus, the required height to provide a reasonable drain time would make the gravity technique impractical. The deficiency of the gravity technique is that the tubing size has to be of sufficient inside diameter to allow adequate flow or otherwise the fluid may clot, particularly if platelets are part of the fluid, and thus impede flow. In addition, if the inside diameter of the tubing is not sufficient this may cause the blood product to flow very slowly because of the relatively high viscosity of the blood related components. Another drawback to the gravity technique is that it only allows blood to flow in one direction, essentially from the blood storage bag to the processing device, unless positions are reversed.
The second technique for moving blood products to a processing device such as a centrifuge is with the use of a pump such as a peristaltic pump. These pumps are functional in terms of flow but their drawback is that they can cause damage to the blood product, particularly red blood cells. The roller wheels on peri-pumps tends to put a significant amount of pressure in a very small area of a tube where the blood is flowing, thereby destroying some of the red blood cells that come into contact with the roller wheels.